#include <iostream>
#include <algorithm>
#include <cmath>
#include <vector>
#include <complex>
#include <queue>
#include <set>
#include <map>

using namespace std;

#define REP(i,a,b) for(int i=a;i<(int)b;i++)
#define rep(i,n) REP(i,0,n)

template<class T> constexpr auto chmax(T& x, T a) { x = max(x, a); }

typedef long long ll;

int T, N;
int c[101], v, vsum[11];
int dp[2][10010];

int main() {

  cin >> T >> N;
  rep(i, N) cin >> c[i];
  rep(atidx, N) {
    int* curr = dp[atidx&1], *next = dp[(atidx+1)&1];
    cin >> v;
    rep(repeat, 10) { vsum[repeat+1] = vsum[repeat] + v; v /= 2; }
    rep(time, T+1) rep(repeat, 11) {
      int ntime = time + repeat * c[atidx];
      if(ntime <= T) {
        chmax(next[ntime], curr[time] + vsum[repeat]);
      }
    }
  }
  cout << *max_element(dp[N&1], dp[N&1] + T+1) << endl;

  return 0;
}